1. Field of the Invention
The present invention relates to a new compound useful as a coloring material, an ink containing the compound and so forth.
2. Description of the Related Art
Compounds with xanthene skeletons have been known as coloring materials having magenta hues and good color developability. Each of the compounds with xanthene skeletons has two high absorption bands (x-band and y-band) in the visible region. The complementary colors of the x-band on the side of longer wavelengths and the y-band on the side of shorter wavelengths are mixed together to produce a hue to be visually recognized, thus providing good color developability. Among compounds with xanthene skeletons, C.I. Acid Red 289 is widely known as a coloring material having a magenta hue and very satisfactory color developability and transparency.
However, compounds with xanthene skeletons, typified by C.I. Acid Red 289, in the related art have a problem of low light fastness. To improve the light fastness of compounds with xanthene skeletons, attempts have been made to modify the structure (see Japanese Patent Laid-Open Nos. H09-241553, 2008-094897 and 2011-148973).
Furthermore, compounds with xanthene skeletons are discolored and spread by water in an environment, in other words, disadvantageously have low moisture resistance. In particular, in the case where a compound with a xanthene skeleton is used as a coloring material for an ink jet ink, the compound has been strongly required to have improved moisture resistance in order to form a high-resolution image, which has been required in recent years. To improve the moisture resistance of a compound having a magenta hue, Japanese Patent Laid-Open No. 2011-012143 discloses that the structure of a compound having an anthrapyridone skeleton and the type of counter ion are specified and that an ink is used in combination with specific crown ethers. However, the modification of the structure of a compound having a xanthene skeleton has not been reported from the viewpoint of improving the moisture resistance.
As described above, levels required for the color developability, the light fastness and the moisture resistance of coloring materials have been increased year by year. However, no magenta coloring material that satisfies the foregoing requirement is present. For example, in the compound described in Japanese Patent Laid-Open No. H09-241553 is bluish as compared with C.I. Acid Red 289 and thus has an unsatisfactory hue as a coloring material for magenta. The compound described in Japanese Patent Laid-Open No. 2008-094897 is distinctly bluish as compared with C.I. Acid Red 289 and thus is inadequate to be used as a coloring material for magenta. The compound described in Japanese Patent Laid-Open No. 2011-148973 has satisfactory light fastness but low moisture resistance. Although the ink described in Japanese Patent Laid-Open No. 2011-012143 contains the compound having an anthrapyridone skeleton, the ink is insufficient for the color developability and transparency as magenta.